The present disclosure relates to an image forming apparatus including a driving force transmitting mechanism transmitting a driving force from a driving source to a rotating member through driving force transmitting members.
An image forming apparatus is provided with a plurality of rotating members, such as a developing roller, a photosensitive drum, and a fixing roller. These rotating member are coupled to an output shaft of a motor, i.e., the driving source, through a gear train and are rotated by a driving force transmitted from the driving source.
Sometimes, such gear train poses a problem that the coupling part between the gears generates noise (meshing noise). In particular, when a rotation speed of the rotating member is increased in association with the increased image forming speed of the image forming apparatus, the noise is tend to become higher in proportion to the increased rotational speed of the rotating member. Still further, in a color image forming apparatus, because a number of rotating member is greater than that of a monochrome image forming apparatus and a number of gear trains is also increased, noise generating spots has increased.
In order to reduce the noise generated from the coupling part between the gears, there is an image forming apparatus in which a drive cover forming a space with a side plate of an apparatus main body is provided and both ends of rotating shaft of each gear of the gear trains are supported between the drive cover and the side plate. There is also an image forming apparatus in which the circumference of the gear train is covered by a sound insulating case having a sound insulating wall.
However, an enough sound insulating effect may not be obtained only by storing the gear train in the space between the drive cover and the side plate. Still further, because the both ends of the rotating shaft of each gear is supported between the drive cover and the side plate, a structure of the drive cover is complicated, thus increasing its manufacturing cost.
Still further, in the case of covering the circumference of the gear train by the sound insulating cover, it may not able to obtain an enough sound insulating effect because the sound insulating wall is not provided on a front side of the gear coupling part. Still further, because the sound insulating wall is composed of a plurality of partition walls, the structure of the sound insulating case is complicated, thus increasing its manufacturing cost.